The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1887-04-17


county is concerned. we lie solely within the
range of Chapter ", or Subcarbonferous or.
stating 1t fully our geolocical place as county
will be found in Volume ii, Chapter Nv, OF the
geological history. So far as Trenton rock IS
concerned, it is contained in the first chapter, or
Lower Silurian.
The next idea to be obtained is the position Of
these five groups Of Indiana rocks. The fact Is;
they are not level but are slightly tilted. with
their upturned edges directed eastward. Hence,
as each group passes westward 1t becomes
deeper. Beginning at the eastern bound
airy of the State, we find Slurian
west as a line connecting Madison. in
Jefferson county, and Peru, in Miami county.
Midway in its course. this line is strongly bent
eastward, to include New Castle, in Henry
county. West of this line, connecting Madison,
New Castle and Peru, We find the Devonan
rocks appearing, and the Silurian dipping be-
meath them About in this Same western
boundary line of surface Silurian lie the towns
Upton and Kokomo. The Devonian continues
westward as the surface rock to q line joining
tho towns of New Albany. Columbus, Indianap-
oils, Frankfort and Monticello. North of the
latitude of Monticello the Devonian is the sur
face rock loverlaid, of course. by . heavy drift
deposit,) across the entire State, with the ex-
ception of q patch OF Siiurian the western
border. Recurring to our western boundary
line OF the Devonian-the New Albany. Indian
apolis and Monticello ine-we find the Sub
carboniferous rock beginning and the Dsvonian
disappearing under them. While in the De-
vonian belt. il it is pierced, the Silurian will be
found underi it. Now, that we have reached the
Subca-boniferous belt. the Silurian must be
reached by piercing both Subcarb oniferous and
Devonan. The western limit of the Subcar-
boniferous, where it is found dipping beneath
the Carboniferous. which there appears as the
surface rock, is line running through
Perry. Martin, Clay, Parke and Fountain coun-
ties, passing west OF US in the neighborhood OF
Veedersburg From thisline westward are Car
boniferous rocks and the coal fields of Indiana.
1t must be remem bered thoue b, THAT Siluran is
still present In the westward area, but is be-
meath the Csrboniferons, Subcar boniferous and
Devonan. AS Trenton rock is the great objective
point-the Mecca towards which all drills are
turned-it becomes interesting to know exactly
its whereabouts. Follow the course Of the drill
in our own county in its search for Trenton rock.
After passing through more or less of drift it
begins to penetrate the Subcarboniferous rocks,
for it must be rendered that these are our sur
face rocks, and the Carboniferous lies of us.
We therefore begin with chapter four in this at
tempt to read backwards, and are of course only
concerned with the preceding chapters, which
lie beneath as. Having penetrated the miscel-
laneous collection of Subcarboniferous rocks,
consisting of sandstones, shales, limestones,
soapstones. etc. and having reached q depth Of
several hundred feet 400 or 500). reach
chapter T three, the underlying Deyoni IAN
feet or more of very dark slate, the
''black slate" or Hamilton slate" and
then a heavy compact limestone is entered, tho
corniferous limestone. The black Hamilton
slate" and the massive corniferous limestone
make up our third chapter Devonian series,
and we have reached depth Of probably 800 or
900 feet and struck into Upper Silurian rock. Or
chapter two Of our Paleozoic volume. Here an
other heavy limestone is encountered called the
Niagara limestone, which we penetrate at q
depth Of about 1000 feet. This lets us into the
Lower Silurian. our chapter first, and we i'm
medistely encounter what is called the Hudson
riv md cho1a han
from 400 to GOO feet Beneath this great shale
deposit we Immediately enter the much coveted
and 1ong-sought Trenton limestone, being the
second member of the Lower Silurian.. and at .
probable depth Of 1.400 to 600 feet To the
east of US, at Kokomo, for instance, the surface
rock is the Niagara limestone, and SO at that
place the drill begins to work. and are read
ing backwards in the second chapter of our
Paleozoic volume instead of the fourth, as in our
own county Hence at Kokomo the Trenton
lies nearer the surface, being found at a depth
Of a little over 900 feet. A boring to the
west of US would have to begin at the last chap
ter of our volume and work back to the first,
and 80 the Trenton would be found several hun
dred feet deeper than with us. Having entered
Trenton rock, there is no need to penetrate it
deeply. A few feet, and perhaps blast. will
determine whether any gas Is waiting to be lib
Grated or not. 1t has become very evident to
every one that Trenton rock does not always
mean gas. Ii that is true, the question arises.
what restricts its occurrence to certain areas OF
more general question. what restricts it to
Trenton2 and why should that formation be so
honored among its brethrenl The answer to
this question lies not In the Trenton, but in the
group of rocks lying just above it. that 400 to
600 feet of shales which We call Hudson river
and Utica shaes. These clay shales form an
impervious stratum, and SO the gas. always
arising, as far as possible, finds in them bar
rier which lies like dam in its pathway, and
below which it has been accommodating and stor-
| ing up pressure for millenniums It would seem,
at first thought. as if it would have
50 saturated the Trenton rock that
be like breaking the rim of dam, but expert
| ence has taught us that two wells may be drilled
| very near together, the one = strong gas we'll,
| the other simply a hole in the ground. The
areas in the Trenton has a twofold answer, VIZ.
/! that it depends upon the character of tho Tren-
| ton and their position 1t must be understood
| that Trenton rock Is not always monotonously
the same. 1t varies, as an ordinary sea-beach
bean from coarse to fine, from loose to compact
material, and its areas of loose, porous perhaps
| shattered material These loose porous areas
| form the so-called gas reservoirs / think some
people have the notion that gas reservoir ID
| some hugh concern filed with compressed gas,
and have been asked it there was not danger
of losing the drills when the 'roof of the reser-
| voir" was pierced. The advantage of shooting a
we'll is to shatter the rock still more, that the
| flow may be freer; or. in tho case of gaslesa
we'll, whore the drill has evidently
struck q compact area of Trenton, il
| is in the hope OF breaking through
to some near-lyine reservoir. Understanding
| than that reservoir means areas of rock ma
terial loose enough to permit the free circulation
! OF gas. it remains to be seen why it does no,
always occur in these. The answer to this has
| to do with the position of the Trenton rocks.
! We have been learning something about Indians
| geology since the advent of natural gas that we
never knew before. The geological strata of our
| State have heretofore had the credit of lying in
fiat sheets, dipping slightly toward the west as
has already been described. They have been
| said to lie like the sheets of paper in book
| But the drill. which has proved to be the hes,
field geologist this State ever had, has revealed
the fact that the deep-lying strata, in certain
| regions of the State are not lying fiat but in
| folds. In these wavelike. folds the Trenton is
included, and so, instead Of lying like a level
plain. 1t has its long lines of low hills
| with intervening valleys The most proninen,
| one of these deep seated folds has reached
| the surface to our north, and lies east and wes
across the State, q great line Of upturnsd
| rocks, yeritable ''rock- DAM" As tho axis oil
this great fold lies roughly in the direction of the
upper Wabash, before it turns uthward, it ha,
been called in our last geological report, the
| Wabash Arch" Parallel folds exist south OF
this. but are deeper seated, while spurike pro
| jections run north and south. In short, if the
surface of the Trenton was mapped or a large
SCALE you would discover it to consist of series
of parallel east and west ranges of low hills
with snort north and south spurs. The exact
| nf oil fbaxo f~1j.